Mitsubishi Denki Kabushiki Kaisha

Mitsubishi Electric Corporation

Yoshio Takada

Tomoaki Kato

Masahiro Kobayashi

Kei-Ichiro Kobayashi

Naomi Furuse

Osamu Wada

Shinji Ishibe

Shoichi Shichimiya

Toshihiro Suzuki

Junichi Shimizu

Takeyuki Maegawa

Iwao Kawamata

Akio Hori

Mitsunori Hama

Hiroshi Nakajoh

A voltage nonlinear resistor is made of a sintered body that mainly includes zinc oxide grains, spinel grains including zinc and antimony as main ingredients, and a bismuth oxide phase, in which the bismuth oxide phase includes at least one of alkali metals selected from the group of potassium and sodium at a ratio in the range of 0.036 at % or higher and 0.176 at % or lower. The voltage nonlinear resistor has good voltage nonlinearity and loading service life characteristics, and can be used for a lightning arrester.

Voltage nonlinear resistor, lightning arrester equipped with voltage nonlinear resistor, and process for producing voltage nonlinear resistor

A voltage nonlinear resistor of a sintered substance of a composite consisting essentially of zinc oxide and containing at least one rare earth element and at least one additional rare earth element selected from the group consisting of Eu, Gd, Tb, Dy, Ho, Y, Er, Tm, Yb, and Lu, and Bi and Sb. Spacing d.sub.n (.ANG.) provided from precipitation grains formed in zinc oxide grains or on a grain boundary lies in the range of 2.85 .ANG..ltoreq.d.sub.1 .ltoreq.2.91 .ANG., 1.83 .ANG..ltoreq.d.sub.2 .ltoreq.1.89 .ANG., 1.77 .ANG..ltoreq.d.sub.3 .ltoreq.1.82 .ANG., 1.56 .ANG..ltoreq.d.sub.4 .ltoreq.1.61 .ANG., 1.54 .ANG..ltoreq.d.sub.5 .ltoreq.1.60 .ANG.. The spacing mentioned here is a spacing obtained according to the Bragg condition in the X-ray diffraction method.

Voltage nonlinear resistor and lightning arrester

A voltage-dependent non-linear resistor member, a method for producing the same, and an arrester equipped with the same. The member is produced by a process comprising the addition of at least one oxide of a rare earth element selected from Y, Ho, Er and Yb in an amount of 0.05-1.0 mol % in terms of R.sub.2 O.sub.3 to a composition which principally consists of zinc oxide and contains bismuth oxide. The member has excellent non-linearity and a high varistor valtage. Further, the arrester has very small size and improved protective properties.

Voltage-dependent non-linear resistor member, method for producing the

A composition for electric material containing as a primary component zinc oxide. The composition further contains at least one of rare-earth elements in a range of 0.01 mol % to 3.0 mol % in terms of oxide thereof given by R.sub.2 O.sub.3 where R represents generally the rare-earth elements, and aluminum in a range of 0.0005 mol % to 0.005 mol % in terms of aluminum oxide given by Al.sub.2 O.sub.3. The composition is suited for manufacturing a resistance element whose varistor voltage can be increased over a whole current range without being accompanied with any appreciable degradation in flatness ratio of a voltage-versus-current characteristic.

Electric resistance element exhibiting voltage nonlinearity

A manufacturing method of an impregnation type cathode for removing emitter material remaining on the porous sintered body pellets, includes steps for impregnating the emitter material into void spaces between the porous sintered body pellets, heating a phosphoric compound in a vessel up to the temperature in a range of about 100.degree. C. to about 300.degree. C., and dipping the impregnated emitter material into the heated phosphoric compound. The manufacturing method of the present invention creates a cathode which operates stably for a long time with high current density because there is no damage caused when the remaining emitter material is removed from the surface of the porous sintered body pellets.

Method of manufacturing an impregnation type cathode

Growing community of inventors

Tokyo, Japan

Yoshio Takada